PI E-871.1A1N, User Manual, Page: 26 / 226

T Page
TAC? Tell Analog Channels 163
TAV? Get Analog Input Voltage 163
TNR? Get Number Of Record Tables 164
Parameters
0x3C Stage Name Positioner name.
Default value: NOSTAGE
String up to 20 characters
4.9.4 Operating Modes
The following operating modes of the E-871.1A1N can be distinguished:
■
Servo mode: Closed-loop/open-loop operation
■
Drive mode: Step mode/linear mode
Servo mode
The servo mode determines whether the motion is performed in closed-loop operation or in
open-loop operation.
■ Closed-loop operation (servo mode On)
The position error that results from the difference between the target position and the
actual position (sensor feedback) runs through a PID servo algorithm (proportional-
integral-differential).
The commanded target position determines whether the motion is executed as a
sequence of linear and step mode or only in linear mode.
■
Open-loop operation (servo mode Off)
In open-loop operation, the E-871.1A1N does not evaluate the signals of the position
sensor.
Whether the motion is done in linear or step mode depends on the motion command sent
and from the following parameter:
■
Q-Motion Open-Loop Driving Mode (0x1F000702)
Information
The E-871.1A1N is intended for closed-loop operation with position sensors (servo mode
On). Servo mode is active after switching on.
►
Query the current operating mode with the SVO? , #4 or SRG? commands.
►
Enable closed-loop operation with the
SVO
command.
Drive mode
Piezo inertia drives are piezo-based drives with virtually unlimited travel range. They use the
stick-slip effect (inertia effect) – a cyclical alternation of static and sliding friction between a
moving runner and the piezo actuator generated by the piezo element – for a continuous
feed of the runner. The operating voltage is therefore output by the E-871.1A1N as a
modified sawtooth signal with a maximum frequency of 25 kHz.
The output of one period of the modified sawtooth signal generates one "step" of the runner.
At rest, the drive is self-locking, requires no current, and does not generate any heat. It holds
the position with maximum force.
In the case of a piezo inertia drive, a piezo actuator acts on a moving runner to generate
motion. The E-871.1A1N supports the following drive modes for piezo inertia drives in open-
loop operation:
4 PRODUCT DESCRIPTION PZ285EN
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1/30/2019
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